1. Field of the Invention
The present invention relates to an apparatus for transferring a liquid crystal display (LCD) panel, and particularly, to an apparatus for transferring an LCD panel for facilitating a transfer of LCD panels of a variety of models.
2. Discussion of the Related Art
A Liquid Crystal Display (LCD) device is a type of display device for displaying images by adjusting the optical transmissivity of individual liquid crystal cells arranged in a matrix using image information supplied as a data signal to the liquid crystal cells.
A typical LCD device includes an LCD panel in which the liquid crystal cells are arranged in a matrix form and driver integrated circuits (ICs) for driving the liquid crystal cells in the LCD panel.
The LCD panel includes a color filter substrate and a thin film transistor array substrate that face each other and a liquid crystal layer disposed between the color filter substrate and the thin film transistor array substrate.
On the thin film transistor array substrate of the LCD panel, a plurality of data lines for transmitting data signals supplied from a data driver integrated circuit to the liquid crystal cells are arranged perpendicular to a plurality of gate lines for transmitting scan signals supplied from a gate driver integrated circuit to the liquid crystal cells. The liquid crystal cells are arranged in areas defined by crossings of the data lines and the gate lines.
The gate driver integrated circuit supplies the scan signals to the plurality of gate lines sequentially so that lines of the liquid crystal cells can be sequentially selected line by line. The data driver integrated circuit supplies data signals to the liquid crystal cells of the selected line through the plurality of data lines.
A common electrode and a pixel electrode are respectively formed at the inner sides of the color filter substrate and the thin film transistor array substrate facing to each other for applying an electric field to the liquid crystal layer. A pixel electrode is formed on the thin film transistor array substrate for each liquid crystal cell. A single common electrode is integrally formed on an entire surface of the color filter substrate. Accordingly, the light-transmittance of each of the liquid crystal cells can be individually controlled by controlling a voltage applied to the particular pixel electrode while a voltage is applied to the common electrode.
A thin film transistor is formed at the respective liquid crystal cells to be used as a switching device to control the voltage applied to the pixel electrode formed on each liquid crystal cell.
In a process for manufacturing LCD panels, a plurality of thin film transistor array substrates are formed on a large mother substrate and a plurality of color filter substrates are formed on another mother substrate. The two mother substrates are bonded, so that a plurality of LCD panels is formed at the same time to improve yield. A cutting process is used to cut the bonded substrates into unit LCD panels.
Typically, the cutting process to make unit LCD panels includes forming a scribing line at a surface of the mother substrate using a diamond wheel having a hardness greater than that of glass and breaking the substrate along the scribing line by applying a mechanical force thereto. Hereinafter, a LCD panel of the related art will be described with reference to the accompanying drawings.
FIG. 1 is a plan view showing a schematic planar structure of a unit LCD panel of the related art prepared by bonding a thin film transistor array substrate and a color filter substrate of the LCD device to each other.
Referring to FIG. 1, an LCD panel 10 comprises an image display unit 13 having liquid crystal cells arranged in a matrix form, a gate pad unit 14 connected to gate lines of the image display unit 13, and a data pad unit 15 connected to data lines. The gate pad unit 14 and the data pad unit 15 are formed on edge areas of a thin film transistor array substrate 1 that are not overlapped by the color filter substrate 2. The gate pad unit 14 supplies the gate lines of the image display unit 13 with corresponding scan signals supplied from a gate driver integrated circuit, and the data pad unit 15 supplies the data lines with image information supplied from a data driver integrated circuit.
On the thin film transistor array substrate 1 of the image display unit 13, the data lines having the image information applied thereto are arranged to perpendicularly cross the gate lines having the scan signals applied thereto. Thin film transistors are formed at each crossing of the data and gate lines to switch liquid crystal cells. Pixel electrodes are connected to the thin film transistors to drive the liquid crystal cells. A passivation layer is formed on the entire surface of the thin film transistor array substrate 1 to protect the electrodes and the thin film transistors.
In addition, color filters separated by a black matrix for each cell area are formed on the color filter substrate 2 of the pixel display unit 13. A transparent common electrode may be formed on the color filter substrate 2.
A cell gap is provided between the thin film transistor array substrate 1 and the color filter substrate 2, which are bonded to each other by sealant (sealing unit) (not shown) formed at the peripheral regions of the image display unit 13. A liquid crystal layer (not shown) is formed in the space between the thin film transistor array substrate 1 and the color filter substrate 2.
FIG. 2 shows the cross-sectional structure of a first mother substrate having thin film transistor array substrates 1 and a second mother substrate having color filter substrates 2, wherein the first and second mother substrates are bonded to each other to form a plurality of LCD panels.
Referring to FIG. 2, for each unit LCD panel the thin film transistor array substrate 1 is longer than the color filter substrate 2, because the thin film transistor array includes the gate pad unit 14 and the data pad unit 15 as illustrated in FIG. 1 at edges of the thin film transistor array substrate 1 that do not overlap the color filter substrate 2.
Hence, on the second mother substrate 30 the color filter substrates 2 formed thereon are spaced apart from each other by a dummy region 31 corresponding to the protruding area of each thin film transistor array substrate 1 on the first mother substrate 20.
Moreover, the unit LCD panels are arranged to maximize the use of the first and second mother substrates 20 and 30. Although the arrangement depends on the model of the unit LCD panels, the unit LCD panels are typically spaced apart from each other by a distance corresponding to a dimension of another dummy region 32.
After the first mother substrate 20 having the thin film transistor array substrates 1 is bonded to the second mother substrate 30 having the color filter substrates 2, a scribing process and a breaking process are carried out to individually cut the LCD panels.
Typically, the scribing process is implemented by forming scribing lines by use of a cutting wheel, while the breaking process is implemented by cutting the substrate along the scribing lines by use of a steam-cutting device.
FIG. 3 shows a substrate 40 processed by the cutting wheel and a pressing bar of the related art. As shown in FIG. 3, a scribing line 33 is formed on the substrate 40 including a plurality of LCD panels 10 using the cutting wheel. The substrate 40 is cut along the scribing line 33 by pressure of the pressing bar.
However, several problems may occur when cutting the substrate using the cutting wheel and the pressing bar as follows.
In order to separate the LCD panel from the substrate that is completely cut by the pressing bar, the cut dummy substrate is lowered below the cut line by gravity. Accordingly, a separate space is required below the cut line. Additionally dust may be generated when the dummy substrate is lowered. Further, if a substrate is not cut into using the pressing bar, the uncut substrate is transferred to later processes resulting in stopping of the later process.